A glassblock is composed by two glass shells, obtained by pressing a drop of fused glass on a stamp and joined together through hot or cold gluing processes creating an internal cavity. The glassblock allow the passage of light in various percentages depending on the colour of the glass and the finishing of the faces of the glass shells.
Glassblocks may be preferred to traditional flat glass for the construction of translucent building envelopes, because of their better performance in terms of thermal and acoustic insulation, fire-resistance (due to the presence of the cavity), light transmission and modularity.
A Dye-Sensitized Solar Module may be composed by a number of Dye-Sensitized Solar Cells (DSC) also known hybrid solar cells.
The typical structure of a Dye-Sensitized Solar Cell is composed of a transparent substrate (for example, glass) made conductive with a thin layer of transparent conductive oxide (TCO) (for example FTO, Fluorine-doped Tin Oxide) and then coated with a mesoporous film of a semiconductor material, commonly the a-toxic and biocompatible TiO2. The photoactive dye molecules are absorbed on the TiO2 surface, constituting the photoanode of the DSC device; then the cell is closed with a counter electrode of a transparent FTO superstrate coated with a platinum film with the function of catalyst. At the end, the device is hermetically closed trough a sealant (such as resins or glass frits) and filled with an electrolyte solution, completing the cell and allowing the mechanism of functioning.
A DSC works by optical molecular excitations, electrons and ions transfers, with a process that mimics the plants photosynthesis.
DSC technologies have recently achieved global levels of efficiency (both as regards cells and modules) that are comparable to silicon-based solar technology that dominates the market today.
The state of the art has already come up with some DSC products on the market. These modules are sold in components or complete packages also suitable for building integration.
The traditional wet assembly system used to build glassblock panels/walls/roofing is not suitable for the construction of high-rise building envelopes made, in particular, of glassblock panels installed outside the vertical plane of the building structure. Precast glassblock panels assembled with mortar and steel rods, because of their structure, can be assimilated to masonry walls, arising the typical disadvantages related to the stress due to the forces perpendicular to the wall surface. The horizontal wind force acting on the panels, indeed, originates flexural deformations of variable entity depending on different factors. Hence, the unsuitableness of the wet assembly system for the construction of glassblock building envelopes, especially in tall buildings, can be easily acknowledged.
The analysis of the state of the art highlighted the existence of several patents showing different solutions for the construction of precast dry-assembled glassblock panels. However, they generally refer to indoor application and not to the construction of building façades. Among the most significant solutions, those referring to continuous or partially continuous profiles—acting as supporting structure of the panels—can be mentioned. These profiles are positioned between the glassblocks, which collaborate actively to increase the mechanical resistance of the panel besides serving as closure elements (i.e. Earl Thompson, Glass block construction assembly, U.S. Pat. No. 5,010,704, 30 Apr. 1991). Patents related to such dry assembly systems essentially differ one from the other for the material used to make the supporting elements (i.e. steel, aluminium, plastic) and for their shape. The aluminium or plastic profiles can then be provided with special housing for the positioning of stiffening rods in order to allow the construction of panels/walls able to bear quite elevated mechanical stresses. Among all the analysed patents, only the one belonging to Shimizu Construction Co. Ltd (no. JP5230899(A) of 1993) foresees the construction of glassblock panels which are prestressed in two directions (vertical and horizontal).